The present invention relates generally to tree shakers for harvesting nuts, fruits, and other tree-borne crops, and more specifically to an improved tree shaker head having an improved assembly for attaching a hydraulically actuated ram within the shaker head.
Tree shakers are known in the art for harvesting nuts, fruits, and other tree-borne products. Shakers typically employ a boom extending forwardly from a tractor or other device, with a shaker head present at the end of the boom for grasping a tree and imparting a shaking force to the tree. The shaker head is positioned around a tree and when the hydraulically actuated ram on the clamp cylinder is energized, pads on the inside of the shaker head compress and conform round the trunk, while subtly twisting the shaker head into alignment. The hydraulic system then sequences from the clamping circuit to the shaking circuit, launching the shaker head into a vigorous shaking pattern during which the crop of fruit or nuts rains down in a cloud of dust and debris. When the shake control is released dynamic braking is applied and the shaker head brakes hard to a stop. The shaker head is then unclamped and the unit moves onto another tree. This process is repeated, often several times a minute depending upon the tree spacing and operator, until all trees in the orchard have been shaken. The shaking action of the device dislodges fruits, nuts, and other products, which then fall from the branches of the tree to be harvested. The shaking action is aggressive, with severe loads imparted to various components of the device, particularly within the shaker head.
The commonly used tree shaker comprises a frame having a hollow welded steel case structure containing the drive sheave, drive belt, two or more eccentric rotating masses, one or more hydraulically actuated rams and hydraulic hose routings. A hydraulic motor typically mounts within or on the top of the case structure and is connected to a drive pulley. A stationary arm is integral to or affixed to the frame. Opposing the stationary arm is a clamping arm which is attached to the rear of the frame by a pivot pin. The clamping arm applies a compressive force during the shaking process when a hydraulically actuated ram is actuated, causing the clamp arm to pivot about the pivot pin and move toward the stationary arm, causing the clamping arm and stationary arm to close about a tree trunk. Once the arms of the head are closed about the tree trunk, vibration is initiated within the shaker head. Typically the shakers use stacked counter rotating eccentric mass energy wheels to generate the vibration or pulse, which is created by the rotation of an eccentric mass about a fixed common shaft. Once the shaking cycle is finished, a hydraulically actuated ram causes the clamping arm to open with respect to the stationary arm.
It is to be appreciated that the various components of the shaker head are subjected to significant loading during the shaking cycle of the above described process, which is repeated almost immediately and repeatedly, but each time all components of the shaker head are twisted into alignment. As a result of this repeated sequence, various shaker head components are continually stressed and subject to wear and failure. The inventor herein has found that some of the most common wear and failure points in existing shaker heads are the end connectors of the hydraulically actuated ram(s) utilized to open and close the clamping arm with respect to the stationary arm, and the structural components of the shaker head to which the end connectors of the hydraulically actuated ram(s) are attached. The end connectors utilized for attaching the hydraulically actuated ram(s) to the clamping arm are typically a clevis type connector as shown in FIG. 2 which is attached to an attachment point on the shaker on the frame or the clamping arm by a pin. Because of the inevitable misalignment of the clamping arm with the stationary arm as the head repeatedly engages trees, followed by the significant loads imposed on these joints as the shaker is engaged, all components of the hydraulically actuated ram and related attachment structures of the shaker head are subject to failure. These failures are expensive to repair and failure typically results in a shaker being idled during the critical harvesting season.